package com.barcode.client.android.encode;

import java.util.Collection;
import java.util.HashSet;

abstract class ContactEncoder {

	/**
	 * @return first, the best effort encoding of all data in the appropriate
	 *         format; second, a display-appropriate version of the contact
	 *         information
	 */
	abstract String[] encode(Iterable<String> names, String organization,
			Iterable<String> addresses, Iterable<String> phones,
			Iterable<String> emails, String url, String note);

	/**
	 * @return null if s is null or empty, or result of s.trim() otherwise
	 */
	static String trim(String s) {
		if (s == null) {
			return null;
		}
		String result = s.trim();
		return result.length() == 0 ? null : result;
	}

	static void doAppend(StringBuilder newContents,
			StringBuilder newDisplayContents, String prefix, String value,
			Formatter fieldFormatter, char terminator) {
		String trimmed = trim(value);
		if (trimmed != null) {
			newContents.append(prefix).append(':')
					.append(fieldFormatter.format(trimmed)).append(terminator);
			newDisplayContents.append(trimmed).append('\n');
		}
	}

	static void doAppendUpToUnique(StringBuilder newContents,
			StringBuilder newDisplayContents, String prefix,
			Iterable<String> values, int max, Formatter formatter,
			Formatter fieldFormatter, char terminator) {
		if (values == null) {
			return;
		}
		int count = 0;
		Collection<String> uniques = new HashSet<String>(2);
		for (String value : values) {
			String trimmed = trim(value);
			if (trimmed != null) {
				if (!uniques.contains(trimmed)) {
					newContents.append(prefix).append(':')
							.append(fieldFormatter.format(trimmed))
							.append(terminator);
					String display = formatter == null ? trimmed : formatter
							.format(trimmed);
					newDisplayContents.append(display).append('\n');
					if (++count == max) {
						break;
					}
					uniques.add(trimmed);
				}
			}
		}
	}

}
